Chapter 15 & 16 Homework Answers Chapter 15 Multiple Choice 6. d 10. c 13. a 18. a 24. a   Problems 4. a) either charges must be zero or the distance becomes infinite b) As r decreases the magnitude of F increases c) d) b 7. 15. Zero 21. 0.58 N positive x direction 24. 2.0 m for the +4.0 nC charge 27. 8.3 N at 49° 35. 40. 2.00 N/C south 42. 46. a) b) right c) d) left e) f) right 48. 11 N/C in the positive x direction 52. 89.9 N/C at 179.857° 55. 57. 61. a) negative b) Tension, electrostatic, gravitational c) d) e) f) g) 63. a) upward b) positive c) upward electrostatic and downward gravitational d) e) f) 71. 4.4 nC   Chapter 16 Multiple Choice 9. c 12. c 17. d 20. c Problems 1. a) 6.0 V b) increases c) d) e) external force 6. 4.50µ J 13.±0.100 V 19. (a) 258 µN (b) 38.7 µJ (c) 38.7 µJ (d) 1.94 V (e) 98 V 27. zero 28. 8.99 km 35. 43. 539 V 48. (a) (b) (c) 0 (d) 0 52. 6.47 kV 59. (a) 0.050 m (b) -45.0 kV (c) Same (d) (e) 63. 0.15 nC 67. 90 mm 72. 77. (a) 12.0 V (b) (c) (d) 1.20 V 79. 89. 2.0 nF 90. 1.0 µF 91. 3.0 µF 97. 10 pF 101. (a) parallel (b) 12.0 µF (c) 24.0 V (d) 288 µC (e) 96 µC 107. 13.0 µF 109. 115. 1.44 mJ 121. 124. 480 µJ